The intention of is to stop Black from getting a framework on the left side. It leads to a rather complex joseki, but professionals regard it as slightly better for Black. Black will defend his left-side position with a or b.
After ,
is regarded as correct. The sequence to
is regarded as joseki, but the general feeling among professionals is that this is slightly better for Black, because coming back to defend at
is too slow.
is too slow because it is unnecessary. If black pushes to cut off
(with a black play at
followed by pushing through) white can complete her outside wall with a play at a and still get good use from
by making life in the corner with a play at e. On the other hand, if the exchange of black f for white g has been made, then white does need to go back and protect her investment with a move around
.
In pro games, has not been played recently - it has to some extent been replaced by White at a, which has been refined by White b, Black c, White a. But often
is d, then tenuki. Charles Matthews
The order of moves in this variation is not strict. Black may play before
, or after
.
Because the result in the previous diagram is considered unsatisfactory for White, other possibilities have been attempted for .
One of them is here. If next Black plays
and
, White quietly connects at
. After
, White still has the invasion at a to look forward to. It is unlikely that White will die if she plays there, but she does run the risk that it is too small to play now. The play at a is basically a very large endgame move, and should therefore be kept for the late middle game.
Black could also play here.
used to be considered joseki. The result is equal to the previous joseki, except for the
-
exchange. Unfortunately for White, Black might well use stronger weapons...
Instead of in the previous diagram, Black could play the crude but severe moves of
to
first. White's four stones are under attack, and if there is a black stone around the middle of the left side (which often there is when this joseki is played), she probably has to search for life with
.
White can live in the corner, but because she has to play to do so, Black can take control of the center with
and
. Black is clearly better off in this diagram.
Because the previous diagram leads to disaster, is considered correct. After
, fighting in this area comes to a temporary halt. Sometimes
is omitted. White could try to exchange White a for Black b before playing
.
See WhyIsThisNotAStarPointJoseki for similar sequences. I'd like to know why they're not joseki (or are they?).
Black's third possibility [1] is the combination of and
, which leads to strong fighting (if
is played at
, we get a transposition to the joseki above). Black should not play this way if the ladder at b works for White, but if it does not, and there are black stones in the neighbourhood to help him, this could become very painful for White.
Rui Naiwei suggests in Essential Joseki that Black 1 is not good simply because black cannot protect A and B at the same time. Has this thinking been outdated? Remillard
After , there is no real alternative to White a. White b is too mild, while exchanging
for
is considered bad because White loses the option of invading at the 3-3 point. This exchange should only be made if White intends to build a base on the upper side, but doing so has been made a priori impossible by
.
The variations after are similar to those after Black a, although there are some differences. One of those is that
is considered not completely out of the question in this position, because White has more difficulties living in the corner, so giving up that option is less of a problem.
See also the go bloopers page, on the 'misplaced slide'.
[1] This cut line has been played frequently in recent pro games; it really needs its own page.
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